Sharpening

sjhong

sjhong

Joined
Jan 28, 2010
Messages
299
I recently got a Magnum Bear Cub and it is my first Busse and convex blade. I'm having some problems sharpening it.

It didn't come sharp and I googled how to sharpen convex and found some videos about the sandpaper and mouse pad method.

Is there a trick to this and I'm not getting it?

I'm using 2000 grit with a soft mouse pad and it doesn't make any difference it doesn't matter how many passes I do. I'm trying to strop it too but the edge still feels very toothy. Is INFI hard to sharpen? Am I applying to much pressure? Too little pressure? Any insights?
 
I've just used some 2000 wet and dry sandpaper on my AMSMO, first try using sandpaper. My knife was dull to the point where it would not slice peppers. Took me a while. I was very careful with the angle. I went very slowly. Took me about half an hour and brought it back to near hair shaving. It now slices tomatoes like a laser.

It seems that you've got to experiment with blade angle, pressure, paper grit, and surface. I placed my sandpaper on a large soft cover novel ( latest Outlander novel:rolleyes:).

Sharpened my NMFBM using a four sided strop bat. I used Black, pink, and green compound. Spend a couple of hours( boy is that knife ever heavy.... And long). Got it hair shaving sharp.

I am no expert and I am curious about what others would have to say.
 
Is the angle that important? I thought the use of a soft base was to eliminate the need for a precise angle.

What gets me is that the guy on youtube did something like 12-16 passes on each side and the knife went back to shaving sharp. Maybe I should keep going until the knife is sharp, doesn't matter how many passes it takes?

Maybe I should buy a cheapo convex edge and practice.
 
sjhong said:
Is the angle that important? I thought the use of a soft base was to eliminate the need for a precise angle.

What gets me is that the guy on youtube did something like 12-16 passes on each side and the knife went back to shaving sharp. Maybe I should keep going until the knife is sharp, doesn't matter how many passes it takes?

Maybe I should buy a cheapo convex edge and practice.
Click to expand...

It all depends on how dull your knife is. Also what steel it is..... And yes, it is a good idea to practice on cheap knives. I must admit to not having many cheap knives..... Learning the hard way;)

I usually put on a movie or tv show and just...... take...... my....... time.... Get faster as you learn. At least that's the way I see it.

As far as the angle is concerned..... The soft surface is going to help. However, you've got to be careful. If you use too much pressure with the wrong angle = to dull knife....not good.

2000 grit is good on INFI, as far as I can tell. Actually did this 2 days ago.... I was pleasantly surprised.
You should search a thread from Lennox. He's got a great one on sharpening. I hope that some else will chime in.
 
Op there are so many threads here on sharpening/stropping. I just read and watched as much as it took to gain an understanding of what I was trying to accomplish with my edge. I then gained technique while using a strop which isn't going to wear your blade. I doubt there is a shortcut to gaining the knowledge or technique, ymmv:p
 
Patience is a virtue, and will yield the greatest results. The satisfaction of knowing that you turned a lump of dull metal into an instrument of hair removal is fantastic. And yes, angle of the blade is super important.
 
sjhong said:
Is the angle that important? I thought the use of a soft base was to eliminate the need for a precise angle.

What gets me is that the guy on youtube did something like 12-16 passes on each side and the knife went back to shaving sharp. Maybe I should keep going until the knife is sharp, doesn't matter how many passes it takes?

Maybe I should buy a cheapo convex edge and practice.
Click to expand...

The angle is not just important it is critical, and when using any deformable medium like a mouse pad or belt sander the pressure must be constant as well.

The reason the slick guys in the video can resharpen with minimal effort is that they perfectly adhere to the existing edge geometry and only a minimal amount of metal must be removed to resharpen. If you do not sharpen to the existing edge angle and shape/pressure, then you must remove enough steel to reprofile at new angle and that is whole lot more work! (but it will still create a sharp edge if the geometry is at least reasonable) If however you have not just the wrong angle, but also an inconsistent angle with each pass, then you will get exactly nowhere ever.
 
Oh boy. That's how is feel. Like I'm going nowhere ever! I hope it does get better.
 
Have your tried a sharp maker? Not that hard to hold correct angle with concentration.
 
IMO, the mousepad technique is not needed to sharpen the factory edge that would likely have come on your MBC. I'd just freehand it on a stone personally…..

[video=youtube_share;OPGGo3W15HQ]http://youtu.be/OPGGo3W15HQ[/video]
 
Red Angel Dragnet said:
IMO, the mousepad technique is not needed to sharpen the factory edge that would likely have come on your MBC. I'd just freehand it on a stone personally…..
Click to expand...

It is important to understand that for the most part only a flexible medium like a mouse pad, leather strop, or belt sander can create a true convex edge. Stones and inflexible sharpeners create V edges. If you switch from one to the other, you must reprofile the edge. Some will doubtless claim that they can resharpen a flat V with a strop, but at least at some level this creates a micro secondary bevel.
 
If I can be of any assistance let me know. If you would like we will resharpen any of our knives for just the cost of the return shipping.

Garth
 
I use a belt grinder (about 600 grit) followed by one of those cardboard polishing wheels on a bench grinder to sharpen. I can get a dull edge to super mirror razor sharp in about 15-20 min (and there are plenty of folks who can do it twice as fast). To do the same work using only 2000 by hand would take me hours if not days. Stropping is generally used only to remove a burr from the edge, not to sharpen.
FYI, I consider most brand new factory edges only "sharp", not sharp enough for me tho. My users get sharpened out of the box.

Patience may be a virtue, but power tools will yield greatest results! ;)
 
mach 5 said:
It is important to understand that for the most part only a flexible medium like a mouse pad, leather strop, or belt sander can create a true convex edge. Stones and inflexible sharpeners create V edges.
Click to expand...

The only way to get a perfect V grind is with some sort of a fixture that holds an exact angle on a perfectly flat sharpening medium. Freehand sharpening on a stone or other flat surface is still going to be convex to some degree, as one cannot be consistent in the angle of sharpening. Most factory edges are only slightly convex in my experience, excluding some of the satin & Limited Edition offerings.
 
Have you tried marking the blade with a sharpie? It will help you see what is actually contacting the sandpaper. A tip I got from Lennox that I found useful was to mark the edge with several lines perpendicular to the edge instead of just coloring the whole edge.
 
Red Angel Dragnet said:
The only way to get a perfect V grind is with some sort of a fixture that holds an exact angle on a perfectly flat sharpening medium. Freehand sharpening on a stone or other flat surface is still going to be convex to some degree, as one cannot be consistent in the angle of sharpening. Most factory edges are only slightly convex in my experience, excluding some of the satin & Limited Edition offerings.
Click to expand...

In the most friendly way possible, I will have to respectfully disagree :D
The video you posted will create a V edge (of course as you point out if it is hand held it is never a "perfect" V edge, but that does NOT make it convex). It is possible to create a convex edge with a stone, but is really painful and frustrating to learn, and I would not recommend it to a beginner. Long time Busse fan Clif Stamp explains it here...

https://www.youtube.com/watch?v=W-nAkkCnkQU

And Murray Carter shows the proper "roll" maneuver needed to make a convex edge with a stone here.

https://www.youtube.com/watch?v=UdEe9sEQRcE

A better option is to use a flexible material, the reason why is well demonstrated here...

https://www.youtube.com/watch?v=tLjBF7klRYY

Look at the wood blocks it shows how most attempts to create a convex edge with a stone end up in a series microbevels rather than a true smooth edge.

My advice in the short term is to take Garth up on his generous offer, and then get a cheap 1 inch belt sander for the long haul :D (pm me if you want my humble advice re a belt sander)

Note to self... Is getting into an e-argument (friendly I hope) with a guy who calls himself "Red Angel Dragnet" ever really wise??? Guess I'll shut up now, peace friends. ;)
 
I have the good fortune to live near Mr. Carter, and have seen him sharpen "live." It seems so simple - like watching Eric Clapton riff on "Key to the Highway." Looks like anyone could do it.

Be sure to learn stropping techniques. Amazing what a cheap, rough Goodwill leather belt and stropping compound (green), can accomplish...;-)
 
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